Liquid flow control



Sept. 22, 1942. 1 w, GREEN 2,296,247

LIQUID FLOW CONTROL Filed April 29, 193B 2 Sheets-Sheet 1 INVENTOR VawmLIQUID mow CONTROL Filed April 29, 1938 .2 Sheets-Sheet 2 INVENTOR.

Patented 1 struction and joperation o liqui treatingdevices o i unodfandfont is .re'asonfthe description: i fwhichtollowsissofar as mapermitsglimited to the specific ieatures provided LPA TxOFFI- v crew; (lcazc; mm or mum a; eorpprat d, aeorporation er Delaware plloatlon April29,; ms. serum; some; i

"This inventid sunburn e inventioncan be applied to other accordancewith my invention;

se e e e-emcee and atypical cycleincludes th sand bed to puriiythe waterand upwardlywas ing the bedgwithwwaterto clean the sand. Addi tional fuctions sirchasdraihing toefliue t surin vention.

direction of flow but to control elrate brew to aratecornmonlyfiiveor'mo times assreat'ias the filtering rate, the illteriii ratebeingusually 2 to 3 gallonspersqua're ioot per minute. The

sequenceit is a serious problem how to cover such a wide range ofquantities bjf controlor measur 1 ing' apparatus which affordsasufflciently precise described and referredto.

Many attempts have bee 1 response and isotherwise adaptediorfthejservice I have involved complications. Pressure diflerene tials werepractically invariably relied their; but

either the mean for}fderiving lor responding to suchdifferentialshave'been duplicated so that 7 two smallranges ofliquidiiowc nbe handled separately, involving excessive costfrfor suchduplicate means; or compound 'rnea have been provided to secure themeasurement f two or more separate ranges by a single devl 11 ,(cl.(F-122,1)- p "iliquid new control andmeasurementand inparticularto suchcon- 1 trol and measurement f or filtering apparatus and the like; Forpurpose or illustration ljwill show anddesc the constructionor-thesamemore complicated and expensive and reducing the emciency' or my m an"in combinatlonwith a f the gravity type-jfor filtering water, i

Thegeneral conow controllers and e filter types are well sci-mm; th 5 Indraining to eiiluent and ma gTto waste, which operations are mm orlessflstandard, the- Sallie rateofiflowv control may beusedas durf ingtheflltering'iunction, but forthe backwash it is generally necessary tonotgom'y reverse; the l n made to provide methods and apparatus for thispurpose; butthese ma in jts measurement andcontrol. "Usually also manualadjustment had to be madein suchdevices incident to each change of fl owrate required byan operating; cycle, adding unduly to the complexity oroperation The alternative method al meas uring flowpver an open weirlsnotegenerally 1 practical for purposesiconsidered hereln due toreasonswhich are obvious to those skilledjin the art, particularlywhereflows are in different directions. ,Because'ot these thingsitis com onpracticetd alternately use two entirely complete and separate flowcontrollers, one for the in: flow andthe othenfor backwashcon InPatentNo. 2,223,623, I hai'efp rbpos'ed,

h with J- n tiamoneot r things i construct arate of-flow controllercovering tw'o ormorefl0w ranges and comprising a singlelbres- *sure"differential derivlngl device, a single difier entialfjresponsive;device, and aplurality'for rate setting members selectively interposedbetween or otherwise selectively associated with said terentialderivingand responsiveifievics, a controller can be constructed without'duplication or or undesirable complications 1:! "the main operatingelement thereof. With the pres- .entjinventionI have carried thesameideas further and in this respect myinvention is arcon-h tinuationin part of saidPatent-No. 2,223,623.

I nowpropose certain structures which are still less complicated andexpensive: than those 'of that application and at the same time asemcient.

Heretoiore tor-control or measurement atlast one measuring orifice ornozzle such as a Vnturi tube has been lnterposedin the system of mainconduits leading to each filter. The larger a filter is, thelargerarethese conduits, a'ndthe larger and more expensive isany suchYentu-rlstructure as has been used. Furthermore, while most or the loss or headprevailing at the throat of such a tube is recovered, the nonrecoverableportion mayrepresentan appreciable part of; the 1 total head availablewhich will in turn shorten];

' filter runs requlrlngrnore frequent bac wa' hingf which meansmore-water and time lost in k5" washing. It isja main advantage ofrhypreseht invention that it obviates the necessity of;such

Venturi tubesor nozzles and so materially*reducesthe cost-ofinstallation and operation ;in-

curredin the prior-practice. w

Another important feature is the substantial saving inspace obtained bythe elimination or the Venturi tube commonly used for. obtaining a ssuredifferential; While so reducing the cost,

I am able to provide a very accurate control and measurement over a widerange of fiows, securing excellent operating results.

It is a general objectof my invention to pro-' vide a measurement andcontrolfor liquid flow and in particular, for multiple fiows, which isfree from the limitations aforementioned, and reduces the costs andcomplexities of installation and operation.

Another object is to provide in a liquid flow system wherein a main flowis divided into a plurality of individual streams and thereafterreunited, control or measurement of fiow from pressure acrossrestrictions necessary to such division.

Another object is to provide liquid treating apparatus wherein flowmeasurementor control is derived from a flow distributing system whichat the same time serves other purposes.

Still other objects and benefits will appear to those skilled in the arton consideration of the following detailed description and of thedrawings appended.

In the drawings Fig. 1 is a plan view of one embodimentofmy invention.Fig. 2 is a sectional elevation of the apparatus shown in Fig. 1, thesection being taken along lines 2-2. V

Fig. 3 is a sectional and enlarged elevation of the actuator shown inFigs. 1 and 2, the section being'taken along lines 3-3.

Fig. 4 is a' partial sectional view showing means ofcautomaticallychanging the control from one rate to another.

Numeral Ill represents a filter battery including filters II and I2, thelatter being only indicatedin part. I3 designates the common infiuentconduit and I4 is an efiiuent and backwash header disposed in pipegallery I5. has an underdrain system including underdrain header, I6 andlateral pipes IT with distributor holes'or openings I8 formed therein,the function of which will be hereinafter referred to in more detail. Inthe preferred embodiment shown, laterals I! are disposed between andprotected by underdrain blocks II! which support graded layers of graveland sand 2I. In the upper part of each filterthe usual wash watertroughs 22 and outlets 2 3 are provided. The flow in the several pipesand conduits may be manually or automatically controlled by thenecessary valves (not shown) as is well understood in the light ofcommon practice.

Flow control valve-s24 are interposed on the underdrain headers I6 andare associated with actuators 25 which include diaphragms or otherdifferential responsive means 26; valve 24 being actuated from diaphragm26 either directly or by means of an intermediate pilot 2! and pressurecylinder 28, or similar devices known to the art. In general the flowcontrol device here shown for purpose of exemplification is of the typeknown from Adelsons Patent No. 1,934,759, there being provided a by-passincluding one or more fixed orifices or nozzles 29 and a variableorifice or other means for varying the proportion of a deriveddifferential effective on diaphragm 26. v

The by-pass wherein said fixed orifice 29 is provided, includes a lead30 connected to the Each filter lower part of filter II outside oflaterals I1 and 7 header I6 by means of a mouthpiece or nipple 30a. Lead30 has two branches 3| and 32, including respectively the valves 33 and34 and connected respectively to the high pressure chamber 35 and,through variable orifice 36, to the low pressure chamber 31 of actuator25. The by-pass also includes a lead 40 which in the embodiment shownjoins underdrain header I6 at a point 40a selected so that fraction lossbetween it and orifices I8 will be minimized. However, the friction losswill be constant for any given flow and can be compensated for if in anycase this should be desirable, by well known means not shown. Instead ofjoining underdrain header I6, lead 40 may join a lateral I! at a pointthat is suitable for the same purpose, and other modi fications willoccur. to any person skilled in the art. Lead 40 as shown has twobranches 4I and] 42 joining respectively low pressure chamber 31 throughvariable orifice 43 and high pressure chamber 35, and includingrespectively valves 44 and 45. The two pairs of valves 33 and 44, 34

and 45, may be adapted to be operated manually or automatically, as willbe hereinafter explained. The variable orifices or openings 36 and 43are preferably formed by the insertion in fixed orifice plates 46 ofshaped plungers 41, the p0 sition of which is adjustable by wheels 48.The

latter may have pointers 49 attached thereto,

which move over graduated scales 50.

By an arrangement of this kind, orifices 36 and 43 can be so adjusted bywheels48 that at desired rates of fiow through the filter, the by-passfiow brings just so much pressure under diaphragm 26 as is suflicientand necessary to balance the weight of the diaphragm and parts mountedthereon. Actuator 25 will then automatically act to maintain the givenrate of filtering or backwash 'fiow through valve 24.

The by-pass described is connected across the orifices in the underdrainsystem comprising underdrain header I6 and laterals I'I. As in modemfiltering practice these orifices are carefully made and proportionedfor the purpose of secura ing uniform distribution of flow the pressuredrop across them is indicative of rate of. fiow the same as adifferential derived by a single orifice. This differential or afunction thereof can be applied on diaphragm 26 and flow governedthereby to any desired rate or rates.

It is obvious to persons skilled in the art how the individual fiows anddifferentials referred to can be calculated and how they can be renderedmore or less uniform, for purposes of flow distribution. It is similarlyobvious that in an underdrain system properly laid out with regard touniform fiow distribution, equal or nearly equal flows occur through allopenings I8, and that in all events the several flows through the sameare proportional and will average to a differential usable for theindicated purpose. Similarly I may also use the'pressure differentialacross any part of the underdrain system or the differential across anyone of the openings between the underdrain system and filterv II,instead of a differential derived in or from the total fiow through all.

The higher pressure will sometimes be on one side of orifices I8 andsometimes the other, depending on the direction of fiow. Duringfiltering water enters the top of the filter through conduitsv I3,flowing down through the sand and gravel, through the orifices I8 intothe laterals I1 and to header I6, and obviously during this period thepressure at 30a exceeds that at 40a.

I filtering.

during backwashing being Conversely during backwashing the water entersthrough 1B,,passing out through orifices] B to rise u through the graveland sand to jclea'nse same.

This reversal ofpressure directionmay beused to automatically shift sthecontroller irom, one con trol rate misnomer-andmeans forthisarelillustratedinflflig. 4.

31s that figureleadsfiil an It is shown wa nected respectively, to l thetop and bottom Icham 'ber oia diaphragm, casing in which is w eights eddiaphragmfSZ, A rod 53,; connected tofdia It will be apparent thatlvalves iii, 34 u, 45,

phragrn 52, passes out thrdughfthecasing andis joined toalink 54 towhich are attached levers.

operating ,valves33, ,3}, l4 and 45. The position didietphriigm 5 2isshown reman-Ma h i in lfl-Iand this pressurjeacts with r han sievin theleversto open valves in; an

tofcloseivalves 34 and A5,,

change loperation filtering to ,baclrwashing the direction of pressurewill be reversed and that urin the filtering valve and stops provided inID will exceed thatin 30. As the-backwash flow is 'necessa-rily verymuchgreater, corrnnonly atleast five times greater than that permissibleduring filtering, obviouslyfthe pressure" difierem tial frornlll tofilidur'ing jbackwashi'ng will be i much greaterthan the tevei-sedifferential during t t ue to this jg reater available pressure'theweight on the diphragm will be 'oyercome and vers .tdclose valves 33anIdNand openvalves l l and 45;, This stops flow through orificeliandopens it through orifice36 which is set to govern to the desiredbackwash rate. On" cessationof'the backwash flow the pressure willequalize and the diaphragm tending to decrease the rate at which thewater fiows into openings l8 and through laterals l1 and header l5;While filtration is going" on,

its plunger may be ,jdispensed with,, permitting simplification of theassociatedpiping fo ming the bypass, but in this event it 'will beldesirable to put shutoff valves in leads 3!) and 4|) to permit openingor removal of the actuator for inspection or repair. Iflp artsT;referred to are omitted, including; ior example; orifice," withitsjplunger, then it will be necessary to reset plunger, l1 associatedwith orifice 36 each time it t i f is desired to change betweenfiltering andback-x washfiofwcontrol. Itis apparent alsowthatlthisplunger may be automatically reset to one position orthe otherrbymeansas shown in Fig.4',,the1 linlg being joinedto plunger 41 instead of tthe to arrest the motion at tij, filter bjed container and the parts,enclosed thereby; The term is not used to include the v conduitfvalvesandyother apparatus which lie outside ojf the filter containerwall. it td liaving now set forthqmyinvention and described a preferred embodimentthereof, Iwish itfunderstood that my invention is not limited by theparticular forms thereof used herein for,

illustrative purposes. Such variations in construction, application andoperation; as are -possible fand permissible and alsmaypccur to those askilled in the art, areintendedto be included in the appended claims.\Iclaim:

"1. In a filter, a container, a filter bed therein,

a flow system comprisingja perforated underdrain underlying said, bedand a conduit joined to said underdrain', avalve in said conduit, a apower operated means for positioning said valve,

a pressure differential member controlling the flow of power to saidpower operated means, and

conduits for transmitting pressure joining said pressure differentialsensitive member to said there will be a tendency to slow up the rate offiow through the filter, which tendency must be overcome by propercompensation for the varying ,55 loss of head. For this purpose; aprimary bypass fiow is established from nipple 300. through lead 1 valve33, branch 3!, high pressure chamber, fixed orifice 29, low pressurechamber 31, variable orifice 43, branch 4|, valve and lead to point 40a;valves 34 and being closed at this time. By applying to diaphragm 26 thedrop of pressure between 30a and 40a, reduced by such head as isabsorbedby orifice 43, I achieve a very accurate and at the same timeanextremely simple control of the filter rate, due to the function ofactuator 28 as aforementioned. Control of the backwash flow, whichbecomes necessary after the loss of head has reached its allowable limitand the flow system has been thrown into backwashing position, is hadjust as simply and accurately in a manner that will be understood fromthe preceding description, the rate of flow governed to the rate set atorifice 36.

flow system between said valve and said filter bed;

andto said container.

2; The apparatus of claim 1 wherein the actuator has a plurality of ratesetting members, and

selector means to render any one of said rate setti ng members operativeat any one time.

3. Apparatus as claimed in claim 1 wherein the actuator has a ratesetting member adapted to be moved to diiferent positions to controlflow to difierent values, a second actuator comprising adiaphragm,conduits oining opposite sides of said last named. diaphragm to pointsinside and outside of said flow system, and a member joining saidlast-named diaphragm to said rate set- ;ting member. 7

4. In liquid purifying apparatus, a granular bed, an underdrainunderlyingsaid bed' having perforations for flow into and from thegranular bed, a rate of flow controlling device connected to saidunderdrain and adapted to be actuated by a pressure diiferential, andmeans for transmitting to said controlling device a pressure dif- I;ierential caused by flow through said perforations comprising pressureconduits connecting said controlling device to the lower portion of thegranular bed and to the underdrain. 5, The apparatus of claim 1 whereinsaid pressure differential sensitive member has a plurality of ratesetting members, means operable to electively utilize any one of saidrate setting members, a second pressure sensitive member operating themeans to electively utilize a rate setting member and conduits fortransmitting pressure joining said last mentioned pressure sensitivemember to said fiow system between said valve and said filter bed and tosaid filter chamber.

6; In a filter unit provided'with a filter bed and valve, and pressureconduits joining said pressure differential sensitive member to pointsin the line of fiow through said apparatus on opposite sides of saidflow openings. Y

8. In filtering apparatus a filter chamber, a filter bed therein, a flowsystem comprising an underdrain system underlying said bed and a conduitjoined to said underdrain system, a valve in said conduit, poweroperatedmeans for positioning said valve, a pressure difierentialsensitive member controlling the fiowof power to said power operatedmeans, and pressure transmitting conduits connecting said pressure'differential sensitive member to a point within said chamber. andadjacent the bottom thereof and a point in the flow system between saidvalve and said filter bed. I

9. A filter unit comprising a filter chamber, a filter bed therein, aflow system partially underlying said filter bed, a flow control valvein the flow system, a pressure difl'erential responsive device forpositioning said fiow control valve,

pressure transmitting conduits connecting said ferential sensitivemember, conduits for transmitting pressure joining said second pressureditferential sensitive member to two spaced points in said filter fromwhich 'diflerent pressures are secured, means connecting said secondpressure diiferential sensitive member to said rate setting means toalter-the rate of flow to a new value on reversalvof pressure relationat said two spaced points.

11. In filtering apparatus a container, a filter bed therein, anunderdrain having perforations for flow into and from the filter bed, aconduit joined to said underdrain, a' pressure diiierential type flowcontroller on said conduit, and means for transmitting to saidcontroller pressure from a point adjacent the bottom of said containerand pressure from within the conduit intermediate the filter bed and thecontroller.

WALTER H. qnnnm.

